Air duct boot



FIG. 1 is a front elevation view of an air duct boot showing my new design;

FIG. 2 is a rear elevation view thereof;

FIG. 3 is a side elevation view thereof, the opposite side being a mirror image of that shown;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof. 

The ornamental design for an air duct boot, as shown and described. 